Service considerations
The following sections discuss service considerations that should be reviewed and practiced before
removing and replacing any system components.
WARNING! When lifting or moving the workstation, do not use the front bezel as a handle
or lifting point. Lifting the workstation from the front bezel or lifting it incorrectly can cause the unit
to fall and harm the user and damage the workstation. To properly and safely lift the workstation,
lift it from the bottom of the unit.
Read cautions, warnings, and safety precautions
For your safety, you must review Service considerations on page 50 before accessing the components
of the workstation. Also, review the Safety and Regulatory Guide that came with your workstation for
more information.
WARNING! Some parts inside the computer will be hot. Power off and unplug the system, and
wait three to five minutes for them to cool before opening the system access panels or touching
internal components.
Electrostatic discharge information
A sudden discharge of static electricity from your finger or other conductor can destroy static-sensitive
devices or microcircuitry. Often the spark is neither felt nor heard, but damage occurs. An electronic
device exposed to electrostatic discharge (ESD) might not appear to be affected at all and can work
perfectly throughout a normal cycle. The device can function normally for a while, but it has been
degraded in the internal layers, reducing its life expectancy.
Networks built into many integrated circuits provide some protection, but in many cases, the discharge
contains enough power to alter device parameters or melt silicon junctions.
Generating static
The following table shows that different activities generate different amounts of static electricity. Static
electricity increases as humidity decreases.
Table 4-1 Static electricity
Relative Humidity
Event 5% 4% 1%
Walking across carpet
Walking across vinyl floor
Motions of bench worker
7,500 V
3,000 V
400 V
15,000 V
5,000 V
800 V
35,000 V
12,000 V
6,000 V
Removing bubble pack from PCB
Packing PCBs in foam-lined box
7,000 V
5,000 V
20,000 V
11,000 V
26,500 V
21,000 V
CAUTION 700 volts can degrade a product.
50 Chapter 4 Removal and replacement procedures ENWW
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